A policy and charging rules function (PCRF) device generates and authorizes a policy and charging control (PCC) rule for a data flow according to factors such as an operator policy, user network access constraints, user subscription data, and service information of a data flow of an application service that is currently being performed by the user, and the PCC rule usually includes a data flow identifier (flow template) and QoS (Quality of Service) information corresponding to a data flow corresponding to the data flow identifier. After generating the PCC rule, the PCRF device installs the PCC rule on a policy and charging enforcement function (PCEF) device. The PCEF device binds the data flow to a bearer according to quality of service in the PCC rule, and this type of PCC rule is referred to as a dynamic rule. In addition, there is another type of PCC rule referred to as a non-dynamic rule (also referred to as a predefined PCC rule), the PCRF knows authorized QoS information and identifier of authorized rule, and the PCRF can activate this type of rule. The PCRF adds the identifier of the rule to an activation message sent to the PCEF device, but the PCRF cannot change the QoS information in the rule.
Generally, one bearer includes one or more service data flows. The PCEF needs to perform an operation for binding the data flow to a bearer according to a PCC rule, that is, to determine a bearer at which the service data flow is located. A basic binding rule is to bind service data flows whose QoS parameters (QoS class identifier (QCI)/allocation and retention priority (ARP)) in the PCC rule are the same to a same bearer. Otherwise, service data flows corresponding to different QoS parameters cannot be bound to a same bearer.
In this way, when a data flow corresponding to a dynamic PCC rule and a data flow corresponding to a non-dynamic PCC rule are bound to a same bearer, if the PCRF performs an operation for changing a QoS parameter (QCI/ARP) on the dynamic PCC rule, a changed QoS parameter is different from the original QoS parameter. Therefore, the QoS parameter in the dynamic PCC rule is different from that in the non-dynamic PCC rule. In this way, two data flows that separately correspond to the original dynamic PCC rule and the non-dynamic PCC rule need to be bound to two different bearers. In this case, a quantity of bearers in a system is increased.
However, in some cases, the PCRF may temporarily change the QoS parameter in the dynamic PCC rule or a QoS parameter of a default bearer, and after a period of time, a current QoS parameter may be restored to the original QoS parameter. For example, in a service that provides prior access to a network for some government officials or emergency management officials when a natural disaster such as an earthquake causes network congestion, the system improves QoS of a bearer of a specific user according to a priority of the user, and further provides a high-priority service for the user. In this case, an increment of the quantity of bearers in the system because of a change of QoS in the dynamic PCC rule is unnecessary. In the transient process, bearers are increased in the system, and system maintenance costs are increased.